From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76206C433EF for ; Mon, 15 Nov 2021 14:50:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A05963211 for ; Mon, 15 Nov 2021 14:50:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232172AbhKOOxa (ORCPT ); Mon, 15 Nov 2021 09:53:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:52892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235137AbhKOOxS (ORCPT ); Mon, 15 Nov 2021 09:53:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 97D9F63210; Mon, 15 Nov 2021 14:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636987823; bh=iJQ0w0jtnSsGPaOWocBuY1kJpQ29nRB99E96u084+lQ=; h=Subject:To:Cc:From:Date:From; b=EJgiOle9cPSQLh7aTbYa3PXah6KlzzGRIFApEJ2WP/asKJl62QabLv/2Nc7usmJ5N KEgwadfHPREANy8twXNfChEbrQUE7gKRmZS8lITzV/LkzBiT0ZsEekQpATTHWsM1ve 61C5JDfUO1kxGhCcrDJEgRNtmVMddhsUtMDa3du8= Subject: FAILED: patch "[PATCH] mm, thp: lock filemap when truncating page cache" failed to apply to 5.14-stable tree To: rongwei.wang@linux.alibaba.com, akpm@linux-foundation.org, cfijalkovich@google.com, hughd@google.com, mike.kravetz@oracle.com, shy828301@gmail.com, song@kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, xuyu@linux.alibaba.com Cc: From: Date: Mon, 15 Nov 2021 15:50:20 +0100 Message-ID: <163698782079143@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 55fc0d91746759c71bc165bba62a2db64ac98e35 Mon Sep 17 00:00:00 2001 From: Rongwei Wang Date: Fri, 5 Nov 2021 13:43:41 -0700 Subject: [PATCH] mm, thp: lock filemap when truncating page cache Patch series "fix two bugs for file THP". This patch (of 2): Transparent huge page has supported read-only non-shmem files. The file- backed THP is collapsed by khugepaged and truncated when written (for shared libraries). However, there is a race when multiple writers truncate the same page cache concurrently. In that case, subpage(s) of file THP can be revealed by find_get_entry in truncate_inode_pages_range, which will trigger PageTail BUG_ON in truncate_inode_page, as follows: page:000000009e420ff2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff pfn:0x50c3ff head:0000000075ff816d order:9 compound_mapcount:0 compound_pincount:0 flags: 0x37fffe0000010815(locked|uptodate|lru|arch_1|head) raw: 37fffe0000000000 fffffe0013108001 dead000000000122 dead000000000400 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 head: 37fffe0000010815 fffffe001066bd48 ffff000404183c20 0000000000000000 head: 0000000000000600 0000000000000000 00000001ffffffff ffff000c0345a000 page dumped because: VM_BUG_ON_PAGE(PageTail(page)) ------------[ cut here ]------------ kernel BUG at mm/truncate.c:213! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: xfs(E) libcrc32c(E) rfkill(E) ... CPU: 14 PID: 11394 Comm: check_madvise_d Kdump: ... Hardware name: ECS, BIOS 0.0.0 02/06/2015 pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) Call trace: truncate_inode_page+0x64/0x70 truncate_inode_pages_range+0x550/0x7e4 truncate_pagecache+0x58/0x80 do_dentry_open+0x1e4/0x3c0 vfs_open+0x38/0x44 do_open+0x1f0/0x310 path_openat+0x114/0x1dc do_filp_open+0x84/0x134 do_sys_openat2+0xbc/0x164 __arm64_sys_openat+0x74/0xc0 el0_svc_common.constprop.0+0x88/0x220 do_el0_svc+0x30/0xa0 el0_svc+0x20/0x30 el0_sync_handler+0x1a4/0x1b0 el0_sync+0x180/0x1c0 Code: aa0103e0 900061e1 910ec021 9400d300 (d4210000) This patch mainly to lock filemap when one enter truncate_pagecache(), avoiding truncating the same page cache concurrently. Link: https://lkml.kernel.org/r/20211025092134.18562-1-rongwei.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/20211025092134.18562-2-rongwei.wang@linux.alibaba.com Fixes: eb6ecbed0aa2 ("mm, thp: relax the VM_DENYWRITE constraint on file-backed THPs") Signed-off-by: Xu Yu Signed-off-by: Rongwei Wang Suggested-by: Matthew Wilcox (Oracle) Tested-by: Song Liu Cc: Collin Fijalkovich Cc: Hugh Dickins Cc: Mike Kravetz Cc: William Kucharski Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/fs/open.c b/fs/open.c index daa324606a41..9ec3cfca3b1a 100644 --- a/fs/open.c +++ b/fs/open.c @@ -856,8 +856,11 @@ static int do_dentry_open(struct file *f, * of THPs into the page cache will fail. */ smp_mb(); - if (filemap_nr_thps(inode->i_mapping)) + if (filemap_nr_thps(inode->i_mapping)) { + filemap_invalidate_lock(inode->i_mapping); truncate_pagecache(inode, 0); + filemap_invalidate_unlock(inode->i_mapping); + } } return 0;